The Standard BSA 200cc Luxfer bottles are rated at 232Bar safe working pressure, there are some rifles that have had 400cc bottles fitted which are marked 200Bar. There is a set of stamped marks around the bottle shoulder area telling you SWP (CP on many bottles) 232Bar. TP 348Bar (test pressure for hydraulic testing) is not to be confused with SWP, WP or CP!
If you have a steel bottle (try sticking a magnet to it) these are no longer considered safe by the original manufacturer (SodaStream) and should be scrapped.